Video time-shifting apparatus
Umted States Patent [19]
[11] Patent Number:
Russo et al.
[45] Date of Patent:
2/1991 Takeshita
6/1991 Schema" ..
[75] Inventors: James
R. Levme, Boca Raton, Fla.
7/1993 vasilescu
['73] Assignee: Gemstar Development Corporation,
8/1993 Goldwmser
7/1994 Vi?'ach .
Pasadsna Califl
5,371,551 1711994 Logan
5,438,423 10/1995
8/1995 Lynch
Related US. Application Data
Moe .... ..
[21] Appl. No,: 388,345
Feb- 14, 1995
Dec. 23, 1997
10/1994 Godwin .
9/1996 Staron .
Primary Examiner—Aristotelis M. Psitos
[63] gfgtanollll?tllll-m-pm of Ser. No. 247,129, May 20, 1994,
Assistant E
.ner_Alan Faber
Attorney Agent, or Firm—Gilford, Krass. Groh. Sprinkle,
Pail-note’ Anderson &
U. .
1. "-61-".-.u...n-n-uwm-n-u-n-“.-u-uuu-u
386/46; 386/
386/72; 386/125; 360/7; 360/75; 360/63;
A video time-shifting system characterized in having a
10-1, 32,
360/75’ 3341 22~ 63» 9-1~ 14-2 14-39 72-1~
72-2, 70; 343/563, 564, 571; 353/331 342;
369/32, 60, 111, 96, 7; 386/46. 52. 55.
57, 60, 64, 65, 68, 69, 70, 72, 109, 125,
continuous recording track acccssed
Separate‘ asychm_
nous read and write facilities enables playback of a video
program to commence from any point in the program while
continuing to be recorded in real time, thus providing
VCR-like program control features such as PAUSE
used to store information relating to various points in the
program so that even upon receipt of multiple PAUSE
commands, the system automatically keeps track of correct
program re-entry. In the preferred embodiment, the storage
References Cited
9/1967 Jones
2/1972 1mg _
__ 274/242
mans takes “1° mm 0f 3 c°n?nu°us ramming ‘rack in ‘1
magnetic disk drive. To prevent discontinuities associated
3/1972 Hull
, 226/118
With the recording and reproducing 0f mate?al rcprcsema
3,855,426 12/1974 Bouwhuis
3/1931 Jagger
3/1982 Hanpachern .
4/1982 Satoh
4,403,309 10/1933 Kieslillg
2/1934 1011115011
4/1934 Y?m?moto
3/1936 Haber! ----- --
4,633,331 12/1986 McGrady
47863” 11/1988 wak’hm ' _
._ 353/4
...... 360/33
.. 360/143
link the diiferent recording tracks into a single, continuous
.. 360/13
recording track, Although program information may be
stored in analog form, digital storage is used in the preferred
-- 360/22
embodiment along with data compression to increase
..... .. 360”
recording capacity The syswm pmfembly furthm- includcs a
video display generator to output for viewing on the display
additionally, symbols relating to one or more points in the
.. 360/331
Pmgmm a“ d/or the time-shifted version thereof.
3/1990 I
' ..
3/1990 (161me ....
tive of the video program, the system preferably incorpo
rates a plurality of write heads, each associated with a
diiferent recording track, and the system automatically
switches from one write head to another so as to effectively
device visual indicia relating to the program and,
4,963,866 10/1990 Duncan
4,972,396 11/1990 Rainer
19 Claims, 2 Drawing Sheets
US. Patent
Dec. 23, 1997
Sheet 1 of 2
US. Patent
Dec. 23, 1997
Sheet 2 of 2
F/G- 2A
3 ’6
1:45 215/, END
video program material is effectively stored in a FIFO
(?rst-in, ?rst-out) butter of variable length so that the user
can view the video material in the sequence in which it is
broadcast. while varying the delay between recording and
playback. Additionally. the “random access" embodiment of
the invention is based upon retrieving stored samples ?'om
This is a continuation-in-part of US. Ser. No. 08/247,129,
?led May 20, 1994 now abandoned.
a memory, thus requiring an algorithm to control the storage
and retrieval of such samples. a complication that could be
avoided through a continuous and uninterrupted recording.
The present invention relates generally to the storage and
retrieval of video programming and, more particularly, to a
system operative to produce a time-shifted version of an
incoming video program to give an operator the type of
control over the program ordinarily associated with local
Therefore there remains an unsatis?ed need for a video
time-shifting apparatus capable of recording a full-length
program without discontinuity and without the need for
extensive, auxiliary bu?‘ering. Such a system should not
only support asynchronous recall of the program, but should
provide a user with sophisticated, VCR~like controls oven‘
the program, such as PAUSE/RESUME. REVIEW,
REWIND, and FAST FORWARD. Additionally, as the user
One reason for the immense popularity of the video rental
industry is that cassette-stored programming gives the
may be interested in accessing particular points in either the
viewer total control over playback operations. Not only can
the purchaser choose to watch a movie when desired, but
also functions such as PAUSE. FASI‘ FORWARD and
incoming or any time-shifted version of the program. facili
ties to communicate playback progress and to mark points of
interest would also prove convenient.
REWlND may be used to take a break from viewing, review
The present invention is directed toward a video time
material of interest. or advance beyond portions which
previously have been viewed or which may be of no interest
25 shifting system including storage means, disposed in a video
to the viewer.
path between a video input and output, and con?gured as a
Programs broadcast in real time do not o?'er such viewer
conveniences. With the advent of cable distribution and the
ongoing increase in channel capacity, a greater number of
video programs will become available. including numerous
feature-length movies. Accordingly, some industry observ
ers have proposed two-way cable systems wherein the same
movie may be broadcast over ditferent channels at slightly
staggered starting times, so that viewers may be able to
switch between these channels. thereby simulating VCR
like operator controls such as PAUSE, FAST FORWARD
and REWlND. However. these schemes do a poor job of
continuous recording track accessed by separate, asynchro
nous read and write facilities. Broadly, under operator
control, reading may occur at any point on the continuous
recording track. and playback of the program may begin
therefrom. thus simulating VCR-like program control fea~
tures such as PAUSE/RESUME. REVIEW. REWIND. and
FAST FORWARD. The system may be disposed in a sepa
rate housing or form part of a video cassette recorder.
television receiver, monitor, personal computer, or any other
piece of equipment associated with the viewing of video
based programming.
simulating operator control, due to the relatively large
temporal transitions involved; furthermore, they are
In the preferred embodiment, the video storage means
takes the form of a magnetic disk drive having multiple,
extremely wasteful of bandwidth. which could otherwise be
used for entirely di?’erent programs. thereby satisfying a
asynchronous read and write heads. and a controller which
links separate recording tracks which may be present on
separate recording surfaces, into a single. continuous record
larger audience.
Sara et al. (US. Pat. No. 5.134.499) disclose an apparatus
for recording video to provide the equivalent of a variable
ing track. More speci?cally, a dual-sided disk is used with a
pair of write heads directly above and below one another,
length “tape-delay,” preferably by way of magneto-optical 45 and the positioning system which moves them as an integral
disc storage. However, recording capacity is limited, and
unit inwrudly and outwardly along a radial path. A pair of
read heads are further provided and mechanically linked
when the record optical head assembly reaches the end of the
track at the outer edge of the disc, it must be repositioned
rapidly to the beginning of the track, which requires the use
above and below one another to access the upper and lower
surfaces of the disk for playback purposes, using separately
of bu?er means to ensure that no signal content is lost during
controlled actuators so that the write and read heads do not
the mechanical repositioning process. Furthermore, Sara et
interfere mechanically. With such a con?guration, the disk
may spin at constant speed, with the write heads moving
slowly as a unit between the inner and outer edges associated
with their respective disk surfaces, with one of the write
al. provide only minimal provisions for control of the
operation of the read optical head assembly, including only
those provisions necessary to position the read optical head
assembly at a particular point at which to begin playback of
heads recording information representative of the incoming
the program material.
Goldwasser et al, US. Pat. No. $241,428 discloses a
video program as a continuous spiral track. When the
writing head reaches an innermost or outermost extent of its
variable-delayed video recorder, including a user control
associated track. recording is immediately switched to the
other write head. and movement of the heads is reversed,
thereby linking the tracks present on the upper and lower
surfaces into a single, continuous track. without the need for
extensive bu?’ering of the program as received. Switching of
panel which enables playback of previously recorded mate
rial to be temporarily stopped and then resumed without
interrupting the recording of new material. If there are
portions of the program that the user does not wish to see
(e.g., commercials), he can speed (i.e., FAST FORWARD)
the read heads, being similarly joined into a physical unit.
through those recorded portions and catch up to the live
broadcast. The user can also rewind and replay portions of
may also immediately switch at such turnaround points, to
65 ensure that readout may likewise occur on a smooth. con
the program as the video recorder continues to record the
tinuous basis. Although. in the preferred embodiment. a pair
program. However, in all embodiments of the invention the
of read and write heads are used in conjunction with a
two-sided recording surface, different write and read heads
may be used in conjunction with different recording
The present invention provides operator control over an
incoming video program, even if such program is broadcast
in real time. Broadly, the invention causes a video transmis
surfaces, so long as the system controller is able to perform
the necessary switching to link separate recording tracks into
a single track so as to avoid discontinuities in the reading
and writing program.
sion in progress to be displayed so as to give an operator the
A memory is used to store information relating to various
points in the program so that, for example, when a PAUSE
command is received, the memory stores information relat
ing to that point in the program. and when a RESUME
command is received, playback automatically commences
from that point, thereby outputting the program time shifted
by the delay between the receipt of the two commands.
When paused, the system preferably outputs a FREEZE
FRAME, and even upon receipt of multiple PAUSE
commands, the system automatically keeps track of correct
program re-entry.
impression that the video program material is locally stored,
thereby enabling functions such as PAUSE and RESUME to
be carried out upon the program material that has already
been received.
Subject to implementation variations described below, the
system automatically and continuously records the incoming
program selected by a user on an associated display device.
If a program-control command is received, the system
continues to store the incoming video program and keeps
track of the exact position in the program associated with the
activation of the particular command. Thus, when a PAUSE
is followed by a RESUME command, the program continues
to be displayed from the point at which it was paused,
In the case of a REVIEW command, previously recorded
points of the program are rapidly accessed and displayed
That is, the program moves backwards while the REVIEW
command is activated, for example, using an associated
although now time shifted relative to the broadcast as
button on a remote control, until such time that the button is
received. The system also preferably outputs a “FREEZE
FRAME” of the program to the display device during
no longer depressed, at which time normal display of the
program commences, but from a point in the program
activation of the PAUSE. The system accommodates mul
previous to real time. The system is also capable of
REWIND in the sense that any previously recorded point of
the program may be immediately accessed, with playback
tiple PAUSE commands, always keeping track of the correct
program re-entry point to ensure that the entire program is
ultimately delivered to an associated display device.
commencing therefrom, similar to a REWIND function with
a VCR in the STOP mode, except that, owing to the
A similar time-shifting occurs upon activation of a
REVIEW command, which causes the program to run
advantageous implementation of the invention, such an
backwards on the associated display device, until deactiva
tion of the command, at which time playback commences,
again resulting in the display of a time-shifted version. If a
operation is carried out in a near instantaneous manner.
If a time-shifted version of the program is being output for
any reason. a FAST FORWARD command may be entered.
in which case playback is speeded up until deactivation of
the command, at which time normal playback resumes,
resulting in the output of the program exhibiting a reduced
time shift, including a zero time shift in the event the
time-shifted version is currently displayed for any reason, be
system preferably furthm' supports the ability to FAST
FORWARD the program, at least to the extent of the time
operator “catches up" with the incoming program as it is
shift, until such time that the operator has “caught up" with
being received.
the incoming program as it is being received. Such time
shifting is not limited to the duration of the original program
broadcast or the immediate time period following, however,
and, in fact, the viewing of the program could be completed
several days later, allowing the invention to function like a
conventional video recorder.
Optional operator controls enable the viewer to jump
ahead in the program, for example, to advance in increments
of 30 seconds so as to avoid the viewing of commercial
The system preferably further includes a video display
generator to output for viewing on the display device visual
Although the foregoing discussion has referred to time
indicia relating to the program and, additionally, symbols
shifted “versions” of the program, the reader should realize
relating to one or more points in the program and/or the
that, in fact, there is only one recorded version of the
time-shifted version thereof. The system is optionally fur
program, that being written onto the recording medium, be
it a tape, disk, and so forth. These time-shifted versions of
the program simply refer to the way in which reading of the
program is carried out for playback purposes.
ther operative to accept a MARK command associated with
a user-de?ned point in the program, and commence play
back diredly therefrom.
FIG. 1 is a block diagram of a system which provides
operator control over an incoming video program utilizing a
disk drive to store video-based information in digitally
compressed form;
FIG. 2A is a drawing of a display generated by the
invention which may be used to provide feedback concern
ing the recording progress and the placement of markers at
user-de?ned points in the program;
FIG. 2B is a version of the display of FIG. ZAwherein the
viewer has moved a cursor in alignment with a previously
set marker to view a time-shifted version of a program as it
Operator control is enhanced by allowing the viewer to
jump forward or backward through the program by pro
grammable steps, for example at 30-second intervals,
thm'eby allowing the viewer a more convenient method to
skip undesirable program material, such as commercial
advertisements. In order to quickly determine those func
tions which a user has carried out, and to access points of the
program in a straightforward manner, the invention prefer
ably includes a means to display visual indicia on the
associated display device indicative of the time shift, and
points of interest in the program, whether inherent or user
available, including the name of the program, start time and
FIG. 1 shows. in block diagram form, a high-level over
view of a system based upon the principles of the invention.
A source of video program material is received over path
104, and video to be played or replayed is delivered along
end time.
line 108 to a display device (not shown). The source of video
is being recorded; and
FIG. 2K3 is yet a further display generated by a version of
the invention wherein schedule information is previously
program material may take any form, including o?-air or
rently is capable of reading or writing data at approximately
eight times the data rate required for compressed digital
video, it necessarily would be required to alternate between
satellite reception, cable transmission, etc., whether in
analog, digital or digitally compressed form. The system
writing, repositioning, reading, and repositioning again,
may also be used when downloading video information ?-om
a computer network. The display may include any type of
which could produce undesirable noise and heat, thereby
shortening the lifetime of the drive and perhaps generating
video monitor, including VGA-format computer video, stan
unwanted visual artifacts in need of correction. This would
also require bu?ering of at least several frames of video
during record and playback operations. As such, the pre
dard television, or HDTV formats.
A system controller 112 receives instructions from an
operator input, shown generally at 160, and coordinates
ferred multiple-head solution eliminates rapid head
record and playback functions of a video storage means as 10
movement, and also eliminates the requirement for buifer
necessary to effectuate a particular command, as described
ing. A separate frame store may, however, be necessary in
herein below.
conjunction with the compression and decompression
engines 107 and 140, respectively, discussed below.
In the preferred rmrltiple-head version of the invention,
Certain of the components depicted in FIG. 1, and in
particular the system controller 112 and storage means, may
be contained within any type of enclosm'e associated with
video processing, including a video cassette recorder (VCR),
a separate enclosure, or such components as alternatively
while the disk drive spins at constant speed, the record heads
move slowly between the outer edge and the inner edge of
the recording surface. When a head reaches its turnaround
may be included with a television receiver, monitor or
point, the recording function is automatically switched to the
personal computer, since the invention resides in large part
next head in the set. As such, data on one surface is recorded
in the manner in which the controller 112 has been pro
from the outer edge to the inner edge, while data on the
surface associated with the other head is recorded from the
inner edge to the outer edge, thus obviating the need for
grammed to ensure the complete replay of an input video
program, even when delayed some period of time from when
broadcast or received in real time.
In a VCR application, although the invention may be
random head repositioning.
In the preferred embodiment. write heads 124 and 126 are
con?gured in-line prior to the cassette recorder portion,
thereby enabling the output video signal to be routed either
located directly above and below one another, respectively,
and are physically joined so that the head positioning
to a display device, or to the cassette, or both, the cassette
apparatus moves both heads radially inwardly and outwardly
recorder portion may instead be con?gured in-line prior to
the apparatus of the invention. As such, the “incoming
video” as de?ned herein may include not only live
broadcasts, but also program material derived from the
as a unit. Using such a structure, then, assuming head 124 is
program along a continuous spiral track with respect to the
upper surface of the disk 116, when the heads are extended
cassette during play. Such an arrangement otfers particular
advantages, including the ability of certain controls such as
time-shift) to respond immediately. thus avoiding any time
delays associated with tape transport. That is, given a
con?guration wherein the cassette plays continuously from
radially inwardly to their greatest possible extent, for
on the lower surface of the disk 116, at which time the write
beginning to end, in the event that such a command is
sentative of an incoming video program is written on a spiral
track de?ned on the bottom surface of the disk 116. When
write heads 124 and 126 have been moved outwardly to their
may instead be used for a more e?icient implementation of
this function, including the ability to review large amounts
greatest possible extent, that is, toward the outer periphery
of the disk 116, the writing process is again switched, now
of program material on an express basis, including jumps
associated with long program sequences, which would be
result in Unnecessary stress on the tape.
example, with head 124 being positioned at the end of track
125, the system automatically switches writing from head
124 to 126, which represents the end-of-track position 125'
heads are jointly moved radially outwardly and data repre
received, instead of actually moving the tape, the invention
impractical through actual tape transport, and which might
currently writing data representative of an incoming video
from head 126 back to head 124. Disk controller 114
coordinates activities of the read and write circuits and head
positioning mechanisms in conjunction with the system
The discussion with respect to FIG. 1 centers on video
controller 112 to ensure a smooth transition between the
storage means in the form of a magnetic disk drive, though
switching of the writing heads, without the need of any
such storage means may take other forms, including mag
netic tape, optical disk, magneto-optical disk, or solid state
memory, for example a very high capacity charge-coupled
extensive buifering.
device, video RAM, and so forth. In a disk-based
con?guration, system controller 112 interfaces with a disk
Although the physical end-of-track positions are used as
the switching points for the write heads, this switching need
not be associated with any physical limit, but instead may
occur with respect to any position on one or more disks.
controller 114, which is responsible for accurate rotation of
the disk 116 and any additional platters 118 rotatable about
axis 120, and also coordinates recording of information
representative of a video program through write circuitry
122, through proper positioning of write heads 124 and 126.
whether single- or double-sided. so long as the switching is
55 used to link individual recording surfaces into a single,
continuous track. Thus, an internal portion of a disk surface
may be used in conjunction with a diiferent, intm'nal portion
of another disk surface, switching between the two surfaces
Additionally, disk controller 114 provides asynchronous
to bring about a continuous writing process without ever
control over replay through read ciratitry 136 in concert
with positioning of read heads 132 and 134.
reaching a physical end-of-track position. Furthermore,
although FIG. 1 shows the two write heads 124 and 126 on
opposite sides of the same disk. though this may represent
The disk drive is of a read/write type similar to those used
in personal computers, but preferably with independent
a preferred con?guration, switching among write heads may
read/write heads, one set being employed for recording, and
alternatively be carried out with respect to diiferent write
the other being used for playback, using separately con
trolled actuators so that the heads do not interfere mechani
cally. Although a typical personal-computer disk drive cur
heads associated with other platters.
In all embodiments, reading of the video-based informa
tion is necessarily carried out asynchronously from the
writing thereof, to provide the operator control features
referenced above. In the preferred embodiment, the read
heads 132 and 134 are similarly directly above and below
compromise, that is, quality vs. recording time, is currently
performed by users when selecting SP-mode vs. EP-mode
recording options in conjunction with video cassette record
ers. In combination with this invention, these compromises
could involve aspects such as compression ratio, spatial or
temporal processing, frame-rate reduction, and so forth.
one another with respect to the same disk 116, the position
ing of which is independently controlled through read cir
cuitty 130. The read heads 132 and 134 also move as a unit
to ensure that if reading must move past a point where
Optional digital-to-analog (D-A) converter 142 converts
the decompressed digital representation of the video pro
switching between write heads has previously occurred,
whether at the end-of-track boundary or otherwise, simul
taneous switching of the read head may likewise occur at
this point to ensure that recall of the video-based informa~
tion may be read out without discontinuity, and without the
need for any extensive buffering with respect to the read
gram back into an analog signal, if necessary, for subsequent
display. Display generation circuitry 144 is used to display
operator prompting messages provided by controller 112, as
well as to indicate points in the program, including a
time-shifted version, as well as the relative delay between
the record time and the playback time. Dashed line 131 is
Operator commands preferably at least include a PAUSE}
used to indicate that in the event the program material was
RESUME function, activated through buttons 166 and 168,
previously recorded in analog form, decompression blocks
respectively, on operator control 160. Depending upon over
all system capability, a FAST FORWARD function 170,
REVIEW or REWIND function 172, and other operator
circuit 130 may be output directly along path 108, preferably
through display generator 144.
140 and 142 may be obviated, and a signal from the read
controls, may additionally be provided. In the preferred
Marker memory 156, which may be separate from, or
embodiment, the controller 160 represents a remote unit,
such as a conventional in?'ared-type (IR) remote controller
unit. which previously may have been made available, as
integrated with, system controller 112, is used to load
information concerning program markers described below,
and to keep track of any other points of interest in the
program which may have been automatically generated by
the system. In the preferred embodiment, using a magnetic
part of a television or VCR system, or may instead be
provided as an integral part of the invention.
System controller 112 preferably takes the form of a
disk for storage, recording surfaces of such a disk are
typically arranged in terms of radially outward spokes
de?ning sectors and concentric rings de?ning tracks. As
microprocessor or microcomputer of conventional design,
and integrates other aspects 152 including a real-time clock
150, read-only memory 152 containing both the software
such, a marker memory 156 preferably stores sector and
track information associated with a point of interest, whether
user entered or automatically generated by the system. to
necessary to carry out the functions described and also an
optional set of prompting messages. graphical symbols, and
enable the head positioning apparatus to move on an express
basis to those track and sector locations associated with a
so forth, and any read/write memory necessary for storing
temporary information. Controller 112 connects to any or all
of the other subsystems, as necessary, to implement the
particular point of interest. Any other approach capable of
particular con?guration selected.
locating program storage locations may alternatively be
105. The output of the AD converter 105 is then preferably
FIG. 2 illustrates ways in which status information may be
conveyed to a viewer through the use of program-related
delivered to a compression engine 107 so as to reduce the
graphical indicia displayed on the same screen as the prc»
If received in analog form, the incoming video is ?rst
digitized by an optional analog-to-digital (A-D) converter
size of the digital representation. Dashed lines 104' and 106'
gram material itself. Although the following discussion
are used to indicate that other types of video signals may be
concentrates of the use of a horizontal bar~type of graphical
representation, it should be understood that other means to
communicate the same information may alternatively be
used directly for recording purposes, including direct analog
recording, digital recording without compression and digital
used, including clock faces and other graphical symbology,
recording of a previously compressed signal. The invention
may therefore take direct advantage of systems wherein the
video signal is in digitally compressed form, including
recently introduced digital satellite systems, and in compli
ance with digitally implemented HDTV broadcast standards.
Regardless of the point at which this compression is
carried out. decompression engine 140 is used to expand the
program back into a non-compressed form. Although blocks
in addition to text or numerical-only formats;
FIG. 2A illustrates one possible display associated with an
incoming program for which detailed schedule information,
including exact starting or ending times is unavailable. Such
50 might be the case if the program is derived from a video
cassette or received in broadcast form through a system
107 and 140 are shown separate from one another in FIG. 1,
these functions, may in fact, be combined into a single
physical entity, such as a programmed microcomputer which
performs a particular compression algorithm in both direc
tions. This algorithm may conform to the Joint Photographic
which does not provide such supplemental information. It is
assume that the display of FIG. 2A and the other displays
discussed below are not necessarily always visible on the
screen, but may appear on a selectively basis, for example,
when a user depresses a button on a remote control.
In FIG. 2A, the horizontal width of the bar 202 is
Experts Group (JPEG, ISO, Standard H.261) Motion Pic
tures Experts Group (MPEG), the newly introduced MPEG
representative of the period of time over which the incoming
H, or any appropriate standard or proprietary method of
of prop-am material actually recorded by the system. It is
reducing data requirements.
This compression engine alternatively may be con?gured
assumed that recording commenced at 11:16 a.m., and that
the present time 3:16 pm. not only are both values option
under system control so as to provide user options in
ally but conveniently displayed, but also an arrow or cursor
selecting a particular compression algorithm or compression
204 is conveniently used to indicate that point of the
program has been recorded, and thus also re?ects the amount
ratio. for example. to enable a viewer to select a lower 65 program now being output to the screen. In the event that the
quality image to increase the available program recording
time for a given amount of storage capacity. This type of
picture is being watched in real time, this arrow 204 will
coincide with the rightmost edge of the horizontal bar 202,
and both will slowly move rightwardly as the recording
arrow 250 has come to rest. Although the times shown in
apparatus continues to store additional amounts of the
incoming programming. FIG. 2A also shows how one or
more markers 206 may conveniently but optionally be
inserted by the user, for example, to mark particular times or
portions in a program to which the viewer might wish to
FIG. 2C have to do with the actual times associated with the
broadcast of the program. alternatively, the user may selec
tively display times relative to the start of the program, even
if actual schedule information has been made available, in
which the leftmost value would read 0 and the rightmost
value would read 2 hours, in this case indicating a two-hour
return. The marker 206, in FIG. 2A, for example, has been
placed at 12 noon. Such markers may be inserted in at least
two ways. Firstly, as the program is being watched, the
viewer sees something of interest to which the viewer may
wish to return, such a mark may be entered irmnediately at
that time, preferably through a MARK function provided on
the remote control. Alternatively, if the viewer later remem
bers something worthy of marking, the arrow 204 may be
dragged back to any previously recorded of the program.
until that sequence is found, then marked, then. if the viewer
Having thus described my invention, I claim:
1. Video time-shifting apparatus, comprising:
an input to receive a video program from a source of such
a video output to view the program on an associated
display device;
video record/playback means, including:
a storage medium having a plurality of circular record
ing surfaces, each with a spiral recording track
having start-of-traek and end-of-track positions.
so desires, the arrow 204 may be returned to any other
previously recorded portion of the program, including real
u'me, with viewing resuming therefrom.
a plurality of write heads to record information repre
sentative of the video program as the program is
received, each write head being associated with a
In FIG. 2B, a viewer has moved the cursor 212 back to the 20
marker at 12 noon, with program being output from that
time. Since the viewer is no longer watching the program in
real time, a marker 214 may be placed at the point associated
with the viewer’s departure from the real time broadcast. In
means for moving the write heads in controlled fashion
this and other cases known to be of interest for the purposes
relative to their respective recording surfaces and
ditferent recording surface and associated spiral
recording track,
of returning to the program, the system itself might auto
tracks. with the apparatus automatically terminating
matically insert the marker 214 to facilitate an easy return to
recording with respect to a given write head upon
that point. That viewing actually recommences at 12:01
p.rn., and that the rightmost portion of the horizontal bar is
already slightly past the marker 214. as it is assumed that the
reaching one of the start-of-track or end-of-track
positions, while immediately initiating recording
operation itself will take one or more seconds to complete.
FIG. 2C illustrates one possible graphical display associ
ated with the recording of a program for which information
about the program is known in advance. including start time,
ending time and, perhaps the title. Such future program
schedule information may be provided either through a
with a different write head, so as to effectively link
the different spiral recording tracks into a continuous
track for recording and playback purposes, and
a read head in cormnunication with the video output
which is capable of accessing the continuous record
ing track asynchronously from the write heads;
a memory for storing information relating to points in the
program; and
a user control in communication with the video record!
downloaded broadcast or in the form of a removable read
only memory, as described, for example. in US. Pat. No.
4,908,713. Thus, in FIG. 2C, the system “knows” that the
playback means and the memory. the user control being
program currently being recorded began at, say, 1 pm. and
operative to:
will end at 3:00 pm. In this case, the width of the horizontal
bar may remain ?xed and indicative of a program length, but
divided into a left-hand already recorded portion 242 and a
cause the memory to store information relating to a
right-hand yet-to-be-recorded portion 244, separated by a
.outputting a time-shifted version of the program
which simulates a PAUSE/RESUME function.
2. The video time-shifting apparatus of claim 1, the user
particular point in the program as it is received and
begin playback from that point after a delay. thereby
delineation 246 indicative of cmrent time. Thus, as the 45
program is received and recorded, this boundary 246 will
slowly move from left to right in this particular embodiment,
control being further operative to:
to convey to a viewer that a larger and larger percentage of
the incoming program is being stored. Conveniently, the left
portion 242 and right portion 244 may be of different
cause the read head to access a previously recorded point
textures or colors, such as green and red, respectively.
Continuing the reference to FIG. 2C, a cursor or arrow
250, similar to that described with reference to FIG. 2A and
213, may be moved by the operator to any point in the section
242, hence the convenient use of a green color for this area. 55
By activating a REVIEW button, this arrow 250 will slowly
move to the left in the diagram, with the previously recorded
portion traversed being output in backwards fashion, much
like the REWIND operation of a cassette tape during PLAY
in the program and begin playback from that point,
thereby outputting a time-shifted version of the pro
gram which simulates a REWIND function.
3. The video time-shifting apparatus of claim 1, the user
control being further operative to:
cause the read head to access a point in the program
associated with a time-shifted version of the program
and begin playback from that point. including points
associated with a reduced time shift. thereby simulating
a FAST FORWARD function.
mode. Alternatively, the operator may simply drag the arrow
4. The video time-shifting apparatus of claim 1, including
a plurality of write heads associated with different recording
250 to any portion of the area 242, and, when movement of
surfaces in a disk drive.
the arrow ceases. playback of the recorded material will
5. ‘The video time-shifting apparatus of claim 1. wherein
the recording surfaces are associated with a magnetic disk
resume from that point in time-shifted fashion, much like a
very fast and direct rewind operation. Regardless of how the
arrow 250 is moved within the area 242, a time may 65
optionally be displayed in conjunction therewith, as being
indicative of that time in the particular program where the
6. The video time-shifting apparatus of claim 1, wherein
the recording surfaces are associated with an optical disk
14. The video time-shitting apparatus of claim 13. the
video display generator being further operative to output for
7. The video time-shifting apparatus of claim 1, wherein
the recording surfaces are associated with a magneto-optical
disk drive.
viewing on the display device visual indicia relating to a
point in the time-shifted version of the program.
15. The video time-shifting apparatus of claim 1. the user
8. The video time-shifting apparatus of claim. 1. wherein
the write heads are radially aligned relative to spiral tracks,
and moved in unison relative to their respective recording
surfaces. such that when the heads have moved radially
control being further operative to enable a user to enter into
the memory a user-de?ned point in the program. and cause
inward or outward to their fullest extent, writing switches
from one head to the other.
9. The video time-shifting apparatus of claim 8, wherein
the pair of write heads are disposed on opposite side of the
same disk.
10. The video time-shifting apparatus of claim 8, wherein
the pair of write heads are associated with di?erent disks.
11. The video time-shifting apparatus of claim 1. wherein
the source of video programs includes a broadcast signal.
12. The video time-shifting apparatus of claim 1. wherein
the video program source is a video cassette.
13. The video time-shifting apparatus of claim 1, further
including a video display generator in operative communi
cation with the video output. video record/playback means
and user control. the video display generator being operative
to output for viewing on the display device visual indicia
relating to a point in the program.
the read head to begin playback from that point.
16. The video time-shifting apparatus of claim 1. further
including a time-keeping device, and wherein the points in
the program are time-related.
17. The video time-shifting apparatus of claim 1, wherein
the recorded information representative of the program is
substantially analog.
18. The video time-shifting apparatus of claim 1. wherein
the recorded information representative of the program is
substantially digital.
19. The video time-shifting apparatus of claim 1, further
including means to record the information in digitally com
pressed form and decompress the information for output to
the display device.
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